This invention generally relates to tools and methods for removing a rivet after it has been installed, and more specifically relates to a rivet removal tool and method which eliminates, or at least substantially reduces, the end load which must be applied to drill out a button and remove a rivet.
Self-piercing rivets are used in many different applications in order to secure two or more work pieces together. When a self-piercing rivet is installed, it is pushed into engagement with the work pieces such that a portion of the rivet expands and the work pieces deform around the expanded portion of the rivet. The expanded portion of the rivet becomes effectively embedded or encapsulated in the work pieces, thereby securing the work pieces together. The deformation of the work pieces causes a protrusion, often referred to as a xe2x80x9cbuttonxe2x80x9d, to form on the other side (i.e. the blind side) of the rivet, and the button includes the expanded portion of the rivet therein.
Sometimes, it is desirable to remove a rivet after it has been installed. One example is when the work pieces have become misaligned, such as during the riveting process. Prior art practices of removing a rivet after it has been installed involve initially grinding off the button. Attempting to remove a rivet by first grinding of the button is undesirable for several reasons. The grinding operation often requires that a relatively substantial end load be applied to the button (i.e. to the grinder which engages the button). This may be very difficult to achieve in light of the position of the rivet and the particular application. Even if it is possible to grind off the rivet, it becomes very difficult to push out the rivet because of the uneven ground surface. Lining up of a push out tool to the ground rivet is done by sight, which may be difficult if the rivet is in a position that is hard to see. This may also distort the hole if not lined up properly making it less likely to put a rivet back in the hole. Additionally, if the grinder slips during the grinding, it may mar the work piece. Finally, the grinding causes dust to spray into the air. This is undesirable and may create a workplace hazard, especially if the dust which sprays into the air is toxic.
A general object of an embodiment of the present invention is to provide a hand held device for drilling into a button, where the hand held device eliminates, or at least substantially reduces, the end load which must be applied to remove a rivet.
Another object of an embodiment of the present invention is to provide a hand held device for removing a button without an end load being applied by the user.
Another object of an embodiment of the present invention is to provide a method of removing a rivet, where the method provides that the rivet can be removed without spraying dust into the air.
Briefly, and in accordance with at least one of the foregoing objects, an embodiment of the present invention provides a hand held device for drilling into a button on a work piece. The hand held device includes a handle which is configured to be actuated to effect clamping of the hand held device onto the work piece. Support structure is connected to the handle, and a drill bit is disposed on the support structure. The drill bit is configured such that the button which is created upon installation of a rivet into the work pieces can be drilled into using the drill bit. Preferably, the hand held device includes a depth adjuster member, such as an adjustable collar, which is disposed on the drill bit such that the depth to which the drill bit drills into the button can be adjusted. The support structure may be generally integral with the handle of the hand held device, or can be provided as separate tooling which is engageable with a conventional hand held clamping device. Preferably, the hand held device is configured to apply an end load to the drill bit, so the user need not do so.
To remove the rivet from the work piece, the hand held device is clamped onto the work piece, a drill is engaged with a drill bit, and the drill is operated to cause the drill bit to drill a recess into the button. Then, the hand held device is un-clamped and removed from the work piece, and a compression tool is used to remove the rivet from the work piece.
Specifically, a push out portion of the compression tool is engaged with the recess formed in the work piece to push the rivet out of the work piece and into a recess provided by the compression tool.
To provide such a compression tool having a push out portion and a recess for catching the rivet, a pair of bits may be provided for engagement with the compression tool, wherein one bit provides the push out portion and the other bit provides the recess for catching the rivet.